Divers are hoping improved weather will allow them to reach wreckage of the AirAsia passenger jet that crashed into the Java Sea a week ago.

Four large objects thought to be debris from the plane have been detected by sonar, but stormy conditions have so far impeded the search.

Flight QZ8501 crashed en route from Surabaya in Indonesia to Singapore last Sunday with 162 people aboard.

Bad weather is believed to be the biggest factor in the crash.

The Airbus A320's "black boxes", or flight data recorders, have yet to be located.

Just 30 bodies have so far been recovered. Most of the victims' bodies are thought to be trapped in the plane's fuselage.

'Window of opportunity'

On Saturday, officials said they had detected four large objects, the largest measuring 18m (59ft) by 5.4m, at a depth of 30m.

Remotely operated cameras were being used to try to photograph the objects, but waves up to five metres high were hampering the effort.

Dozens of divers from Indonesia and Russia have been deployed for the search operation.

"We hope lower waves will give us a better result today," said National Search and Rescue deputy chief Tatang Zainudin. "We are racing with time and weather in running this mission."

Rukman Soleh, the weather bureau chief at the search headquarters in Pangkalan Bun, said the weather on Sunday and Monday "should provide the search effort with a window of opportunity".

Another search and rescue official, SB Supriyadi, said 95 divers were on standby.

"We'll be concentrating on the underwater search, hopefully we'll be able to evacuate more bodies," he told AFP news agency.

"We want to speed up the evacuation of bodies which might be stuck inside the plane's body."

The Indonesian weather agency, BMKG, said that conditions at the time of the plane's disappearance suggested it had probably flown into a storm.

It said initial analysis suggested icy conditions in the air had caused the engine to stall.

Officials have said the plane was travelling at 32,000ft when the pilot's last communication was a request to climb to 38,000ft to avoid bad weather.

AirAsia did not have official permission to fly the Surabaya-Singapore route on the day of the crash, but was licensed on four other days of the week.

The Indonesian authorities suspended the company's flights on this route pending an investigation. AirAsia has said it will "fully co-operate".

There were 137 adult passengers, 17 children and one infant, along with two pilots and five crew, on the plane - the majority Indonesian.

Families of victims have been holding funerals as bodies that have been recovered are flown back to Surabaya.

AirAsia previously had an excellent safety record, with no fatal accidents involving its aircraft.

BBC